AC troubleshooting

[solarboy]

Hi there, 1st post apologies for starting with a question!
I am trying to narrow down the non-working standard (not climate control) AC on my 2001 Polo 6N2 1.4 TDI. The light DOES come on with the switch, she is fully gassed up (I forget the actual pressure I read as it was a few months ago but it was within spec), there is NO POWER at the ambient temp. sensor near the pollen filter.
I'm thinking next thing to check would be the high/low pressure sensor but it's a pig to get to involving removal of the front bumper so I was hoping for a 2nd opinion.The compressor doesn't kick in (no drop in RPM nor "clunk").
Any ideas?

[alexperkins]

Welcome

Check the compressor is actually plugged in - they often get damaged/disconnected when people change the oil filter as the plug is very close

Have you had the car scanned on VCDS at all

[solarboy]

Thanks for your swift reply ! Amazing ! I have a Vagcom lead and it didn't flag any errors. Would it throw an error if it's only AC and not CC? Also, which controller would I look at?
I will also check that connector now !

[alexperkins]

If its standard AC then no, perhaps not. Do an autoscan of all controllers for faults and see what it comes back with.

[solarboy]

Good idea! I checked that 2 pin connector on the compressor, just reads 4.5V (stray voltage I presume) whether the AC is on or off or even if the ignition is on or off.
With Vagcom, no fault codes and no AC controller found.

[alexperkins]

Should be 12V on the compressor with AC switched on

Sounds like its not registering the pressure in the system, or it thinks its too cold outside

[solarboy]

Yep I think you're right, and the hi/lo switch must come before the ambient sensor..so bumper off etc ! At least it aint the compressor.
Thanks for your help !